Back in 1990 when I did the first rebuild of my 455, I instructed the machine shop to crossdrill my crankshaft and chamfer the oil holes. Unfortunately, I didn't notice at the time, but the chamfers aren't very well rounded...they've actually got some fairly sharp edges on them. While tearing down the short-block this evening, this is what I found. (click thumbnails to enlarge)



You can see a burr on one of the holes (marked as #1), a part of which apparently broke loose and caused a very slight circular scratch on the journal which goes maybe 1/3 the way around, but isn't deep enough to even catch your fingernail on, and a slight deformation about 1/2" long (marked as #2). I can just barely catch my fingernail on this deformation. Not marked is a similar deformation above the other oil hole...if I try real hard, I can feel it with my fingernail.

The burr put a pretty good scratch on the rod bearings, seen here:



Since the engine only had 250 miles on a fresh-ground crankshaft (.010/.010) and I had great oil pressure (cracked a head, so the engine got pulled and stored), is this something I need to address? If possible, I'd like to try rounding off the sharp edges of the chamfer. Can this be done at home...maybe with a Dremel? Or should I take it to the machine shop and let them deal with it? Can the journals be polished without adversely affecting the bearing clearance?

 

Just send it out and have them crank shop polish it. If it was me I would chamfer the oil holes more. But that is just me.

Gene

 

If it was me, I'd take the crank and bearings back to the shop and explain how you were lucky to tear it down and find this problem before it wiped out the bottom end!
A good, reputable shop should/would polish the crank and replace the bearings at no charge!
Especially with only 250 miles on it!

 

250 miles and 21 years, i douth if the shop will do much for you now.

 

Any of the shops I worked for/with would take care of it - no charge!!
Doesn't hurt to ask!